The present invention relates to a gearshift mechanism for a synchronized gear change transmission having a gear shift sleeve displaceably supported on a synchronizer body, which can be brought into operative engagement with a gear wheel by means of at least one synchronizer ring, such that, to support the synchronization process, first and second recesses are formed in the inner peripheral face of the gearshift sleeve and locking blocks with a spring-loaded ball which engage in the recesses in certain shift positions are provided on the synchronizer body, such that the recesses have lateral slopes by means of which the axial contact forces applied against the synchronizer ring can be produced with different force peaks in cooperation with the ball as the gearshift sleeve is displaced, characterized in that, for a preliminary and subsequent synchronization, the first and second recesses formed in the inner peripheral face of the gearshift sleeve are radially and axially offset relative to one another and each cooperates with a spring-loaded ball.
DE 44 04 093 C2 describes generic gearshift synchronization, proposing two recesses formed in succession in the inner peripheral face of the gearshift sleeve and separated from one another by overpass edges to
prevent so-called gear grinding in gear synchronization. When the gearshift sleeve is displaced, these two recesses cooperate with a spring-loaded ball fixed in a locking block in the synchronizer body. With the second recess directly adjacent to the first recess, a second peak of force is produced via the spring-loaded ball, by which a corresponding subsequent synchronization can be achieved.
An object of the invention is to further improve preliminary and subsequent synchronization for a synchronized gearshift mechanism.
This object has been attained by providing that for a preliminary and subsequent synchronization, the first and second recesses formed in the inner peripheral face of the gearshift sleeve are radially and axially offset relative to one another and each cooperates with a spring-loaded ball.
Through radially and axially offset recesses formed in the inner peripheral face of the gearshift sleeve, greater freedom in the geometric configuration of the recesses and/or the spherical bodies cooperating with the recesses can now be advantageously achieved. As a result, the axial overthrust forces with force peaks of different magnitudes necessary for optimal preliminary and subsequent synchronization can be generated.
By a different geometric configuration of the first and the second recesses or the spring-loaded balls cooperating with the recesses, the optimal overthrust forces required for preliminary and subsequent synchronization can also be generated.
In addition to the different geometric configuration of the recesses and/or the balls, different spring characteristics may also be used to influence the overthrust force.